This composite image shows the South polar vortices at Venus (left) and Saturn (right).
The left image was taken by the Ultraviolet/Visible/Near-Infrared spectrometer (VIRTIS) on board ESA’s Venus Express on 29 May 2006, from a distance of about 64 000 kilometres from the planet. The vortex is imaged at a 5.05-micron wavelength, corresponding to an atmospheric altitude of about 59 kilometres, just about the Venusian cloud deck.
The right image was taken in October 2006 by the Visual Infrared Mapping Spectrometer (VIMS) on board NASA’s Cassini, at a 5-micron wavelength. The large number of dark, circular leopard spots indicates that convective activity extending over dozens of kilometres in altitude is surprisingly rampant in the south polar region. Literally hundreds of storm clouds encircle the pole, appearing as dark spots in this image. Each of these spots represents a storm.